Importance of Quality in Dietary Supplements (Part 1)
Posted Thursday, August 7, 2008

By guest blogger Paul Van Ness

With approximately 150 million Americans taking dietary supplements on a regular basis,i there have been increasing concerns over the quality, safety and efficacy of these products. CNCA believes it’s important for consumers to understand these key issues and be able to make informed decisions about the supplements they purchase.

Dietary supplements include vitamins, minerals, herbs and specialty supplements. With the multitude of products and brands available, consumers are faced with difficult decisions in selecting the safest and highest-quality supplements. In response to these issues, a number of quality certification programs and good manufacturing practice guidelines have appeared,ii,iii but despite these advances, much of the burden of producing quality supplements falls on manufacturers themselves.

Fortunately, there are ways that knowledgeable consumers can empower themselves to make informed decisions when selecting supplement products. Knowing what to look for on supplement labels and what questions to ask a supplement company before purchasing their product can help assure consumers that their dietary supplements are of the highest quality and safety.

The Quality Trinity
Quality in dietary supplements can best be defined by three criteria: purity, potency and authenticity. It is by carefully evaluating its products for each of these factors that a supplement manufacturer can be certain of the quality of its products.

Purity is the measure of a product’s freedom from biological and chemical contaminants. Pure supplement products are free of dangerous chemical and biological toxins.

Potency is reached by ensuring that ingredients and finished products are verified effective using validated methods. Testing for potency measures a product’s active components and strengths. Potent supplements contain the labeled amounts and potencies of active ingredients.

Authenticity involves verifying the identity of ingredients using validated methods. Testing for authenticity assures that labeled ingredients are indeed in the bottle.

Dietary supplement companies must be in active pursuit of this trinity of product quality. To help guide manufacturers in this pursuit and to inform consumers of products and manufacturers they can trust, quality certification programs and current good manufacturing practice (cGMP) guidelines have been developed to evaluate supplement products for each of the three issues above.

This is the first of three articles about supplement quality. Part 2 will cover certification programs and FDA guidelines.

Paul is Managing Director at CNCA (, which provides a superior quality, doctor-developed brand of dietary supplements used in hospitals and clinics and sold to quality-concerned consumers across the US. Paul also serves on the CNCA Quality Unit. He can be reached at

i Consumer Health Information Corporation. “Dietary Supplements: What You Need to Know.”
ii National Center for Complementary and Alternative Medicine [NCCAM]. “Pros and Cons of Current Certification Programs Industry.”
iiiU.S. Food and Drug Administration. “Fact Sheet: Dietary Supplement Current Good Manufacturing Practices (CGMPs) and Interim Final Rule (IFR) Facts.

guest on August 23, 2008 at 10:28:28 am

As important as the Quality trinity is, an even more important requirement for drugs is EFFICACY. What data support the claim that these supplements actually do anything to improve the health of the user?

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